O2 sensor

[flexdog]

I got a 1991 ford explorer edddie baurer V6 four wheel drive and I want to change out my O2 sensor because I am getting a lean reading on my OBD

I was wondering if any body knows how many there are and which ones I have to change in order to get the right signals to the computer so it will stop dumping so much fuel into the injectors

thanks

 

[ChasAld]

One O2 sensor - on top of the exhaust just in front of the cat. converter. Vacuum leaks are a major cause of lean O2 readings. Might be wise to do some checking in this area before you start replacing sensors. Sensors can get to be expensive and will not always solve a problem caused by another fault.


charles

 

[flexdog]

pre and post

So are there two one pre and one post cat
I'm thinking its the O2 because the engine is brand new from ford and only has 25000 on it
also the check engine light only comes on after the engine is fully warmed up
something about open loop i think

 

[rwenzing]

There are no post-cat O2 sensors on a 91.

 

[flexdog]

thanks

thanks for the reply
think I'll change it since its just one and its not too expensive

 

[mawrazen]

My 94 has 2 O2 sensors, left side and right side. They are between the exhaust manifold and cats.

Quite often replacing O2 sensors does not solve the problem. The issue lies elsewhere.

I was getting a CEL light with O2 codes. I installed an Air/Fuel gauge and did the throttle cable mod. Havent had a CEL in 2500+ miles since.